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Development of titanium dioxide for photo-electrochemical hydrogen production

  • Authors: Mbulanga, Crispin Munyelele
  • Date: 2019
  • Subjects: Titanium dioxide , Nanostructured materials Water chemistry Environmental chemistry
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/40735 , vital:36231
  • Description: TiO2 is an attractive material for photo electrochemical hydrogen production and in this work the synthesis of this compound by hydrothermal, gel-calcination and one-step templating methods is investigated. Rutile-phase TiO2 rods, which are known to offer direct electrical pathways for photo generated electrons when using TiO2 as a photo anode in a photo-electrochemical hydrogen cell, were prepared on both F:SnO2 (FTO) coated glass and Ti foil substrates. Anatase-phase TiO2 tubes and mixed rutile-anatase-phase TiO2 nanostructured films were developed on FTO-coated glass substrates. Rutile-phase TiO2 rod-like structures, were synthesized hydrothermally at 150 oC for different times (6 – 20 hours) on FTO-coated glass substrate, in an aqueous solution of hydrochloric acid and titanium butoxide. The rod-like structures were found to comprise bundles of crystalline prismatic TiO2 nanorods, each approximately 4 nm in width. Each bundle was tetragonal in shape and highly oriented with respect to the substrate surface. The average diameter of the bundles varied depending on the growth time, and reached a mean diameter of ~175 nm after 20 hours of growth. In terms of Raman scattering, these bundles of nanorods acted as single entities, appearing to act as “larger” crystals to the lattice phonons. Hence, phonon confinement effects could not be observed, because the translational symmetry is preserved at the boundaries between individual rods. Moreover, as the preferential perpendicular orientation of the bundles improved with growth time, an unusual increase in the room and low (77K) temperature Eg/A1g Raman band intensity ratios was observed. The low temperature Raman peak position and peak width data was interpreted as supporting the hypothesis that the bundles of nanorods acting as single entities from the point of view of the lattice phonons. The phonon symmetries and frequencies (in cm-1) of these bundles of rutile-phase TiO2 were found to be consistent with rutile-phase TiO2 phonon symmetries and frequencies. Rutile-phase TiO2 rod-like structures were prepared on Ti foil following a two-step gel-calcination method, which involves a gel-deposition process in 5 M NaOH solution at 76 oC for 24 hours to produce a Na- (and Ti-) based layer of gelatinous material, followed by calcination at 600 oC or 800 oC for 1 hour. It is shown that the use of an alkali-based solution such as NaOH and KOH during gel-deposition, leads to the formation of faceted nanorods of rutile-phase TiO2 upon calcination at high temperature. When a solution that does not contain any alkali element, such as H2O2, was used, the material formed upon calcination at 800 oC were clustered nanoparticles, rather than nanorods. From the experiments it was deduced that the high temperature calcination step converted the Na(or K)-based amorphous gel (formed on the Ti surface during a 24-h soak in NaOH (KOH) solution) into faceted Na-titanate rods, which converted into nanorods of rutile-phase TiO2 when Na(or K) evaporates in the form of an oxide. Anatase-phase TiO2 tube-like structures were produced by a one-step templating solution approach, on FTO-coated glass substrate. ZnO nanorod templates were prepared by chemical bath deposition on FTO-coated glass substrate, and then treated in an aqueous mixture of ammonium hexafluorotitanate and boric acid. To study the effect of the template morphology and deposition processes on the formation of anatase TiO2 tubes, different times (10 – 60 minutes) and concentrations of the precursors are used. Calcination at 550 oC converted the Ti-based material developed on the ZnO rods into TiO2 nanostructures. A 10 minute deposition yielded tubes with dimensions resembling those of the ZnO template. However, the tube walls still contained Zn traces. Based on experimental observations, it was concluded that the production of titanium hydroxide complexes on ZnO surfaces takes place through two competing processes: the development of a Ti-based material and partial dissolution of ZnO along the c-axis. Calcination at 550 oC in air finally yielded anatase TiO2. Mixed rutile-anatase-phase TiO2 nanostructured films on FTO-coated glass substrate were prepared by decorating bundles of crystalline prismatic TiO2 nanorods (prepared hydrothermally) with anatase-phase TiO2 particles, using the same precursors mentioned above. The effect of reaction time and precursor concentrations were investigated. It was found that the precursor concentration ratio and reaction time played key roles in controlling the decoration process. Optimal ratios and decoration times were established based on the density of anatase-phase TiO2 decorating particles on the surface of bundles of rutile-phase TiO2 nanorods. The optical properties of rutile-phase TiO2 rods were investigated. The thickness of the TiO2 layer was calculated from reflectance fringes, and agreed well with the length of rods observed using SEM. The room temperature absorption edge of Eg=2.90 eV extracted from the transmittance spectrum correlated with typical values reported for TiO2. The room temperature absorption edge of the conductive layer of F:SnO2 (Eg=3.56 eV) could also be extracted from the transmittance spectrum. Finally, the absorption of white light by rutile-phase TiO2 rods was confirmed to be enhanced by annealing the rods in either hydrogen or nitrogen at 600 oC. Defects (possibly oxygen vacancies) or disorder in the near surface layers of TiO2 induced during the reduction experiments, created new electronic states in the band gap, as reported in literature.
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  • Date Issued: 2019

Development, manufacture and characterization of niosomes for the delivery for nevirapine

  • Authors: Witika, Bwalya A , Walker, Roderick B
  • Date: 2019
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/183514 , vital:44002 , xlink:href="https://doi.org/10.1691/ph.2019.8168"
  • Description: Nevirapine (NVP), used for the treatment of HIV/AIDS, exhibits unpredictable oral bioavailability, has a poor side effect profile and requires frequent dosing. Niosomes are novel drug delivery systems that have the potential to overcome these challenges. A thin layer hydration approach was used to produce niosomes and optimisation was undertaken using design of experiments (DoE) and response surface methodology (RSM) establish and identify parameters that may affect the manufacture of niosomes. The impact of cholesterol and surfactant content, hydration time and temperature on manufacture was investigated. Critical quality attributes (CQA) in respect of particle size (PS), entrapment efficiency (EE), polydispersity index (PDI) and the amount of NVP released at 48 hours was also assessed. The optimised niosome composition was identified and manufactured and the CQA characterised prior to placing the batch on stability for 12 weeks at 4±2 °C and 22±2 °C. The PS, PDI, EE and % NVP released at 48 h was 523.36±23.16 nm, 0.386±0.054, 96.8 % and 25.3 % for niosomes manufactured with Span® 20. Similarly, the parameters were 502.87±21.77 nm and 0.394±0.027, 98.0 % and 25.0 % for mean PS, PDI, EE and %NVP released at 48 h for Span® 80 niosomes. All characterisation was undertaken on the day of manufacture. In conclusion, a simple, cheap, rapid and precise method of manufacture of NVP niosomes was developed, validated and optimised using DoE and RSM and the product exhibited the target CQA.
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  • Date Issued: 2019

Devulcanisation of truck tyre tread vulcanisates in supercritical carbon dioxide using diphenyl disulphide and 2,2- dithiobis(benzothiazole)

  • Authors: Mabuto, Briswell , Ogunlanja, A
  • Date: 2019
  • Subjects: Vulcanization , Polymeric composites Rubber Carbon dioxide -- Thermal properties Environmental chemistry
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10948/40702 , vital:36224
  • Description: A lot of work has been done in the recycling industry in an effort to increase the amount of reclaimed rubber used in new tyre formulations. The major drawback has been inferior physical and mechanical properties of reclaimed/virgin rubber blends in comparison to the virgin rubber material. Deterioration in these properties has been identified to be a result of chain degradation during reclamation processes as well as presence of crosslinks in the final reclaim product. Devulcanisation techniques have gained precedence due to the relatively improved properties of devulcanised/virgin rubber blends. The concept of devulcanisation is to reverse vulcanisation, resulting in total or partial cleavage of crosslinks. In this way, chain degradation is minimised while crosslink scission is maximised, thereby resulting in good quality devulcanised rubber. However, due to the persistence of chain degradation and crosslinks during devulcanisation processes, a very limited number of reports have claimed success in achieving this goal. Therefore there is still the need to develop a devulcanisation method that ensures improved quality and productivity of devulcanised rubber. Typical truck tyre tread vulcanisates were used for optimisation of time, temperature, heating rate, pressure and amount of devulcanising agent while monitoring percentage devulcanisation in supercritical carbon dioxide medium. Optimisation of the devulcanisation conditions was done by employing a twolevel central composite design in the isothermal and non-isothermal heating stages. This was followed by a single factor analysis of devulcanisation conditions in the non-isothermal stage. The effect of the presence of carbon black was investigated by comparing the percentage devulcanisation of carbon black filled and unfilled samples. The results show that supercritical carbon dioxide is an effective medium of devulcanisation using diphenyl disulphide (DD) and 2,2-dithiobis(benzothiazole) (MBTS). The relatively higher degree of devulcanisation observed during the non-isothermal stage compared to the isothermal stage, led to a shift of focus to non-isothermal devulcanisation. Temperature and time were found to have a significant antagonistic effect on the percentage devulcanisation, while changes in pressure above critical point and mass of devulcanising agent showed no effect on percentage devulcanisation. The heating rate was determined by the set-point, of which 180 ℃ set-point temperature resulted in desirable degree of devulcanisation for both DD and MBTS. 76.18 ± 5.50 % devulcanisation in 5 minutes at 102 ℃ was observed for DD whilst 70.92 ± 4.10 % devulcanisation in 4 minutes at 97 ℃ was observed for MBTS. Changes in pressure above critical point and mass of devulcanising agent used in devulcanisation showed no significant effect in the percentage devulcanisation and so they were kept constant at 80 bars and 1.00 % v (of weight of rubber sample) devulcanisation agent, respectively. The presence of carbon black was found to have an effect on the degree of devulcanisation; 87.95 % and 81.33 % devulcanisation was observed for unfilled samples devulcanised using DD and MBTS respectively. Thermogravimetric analysis of the natural rubber/styrene butadiene rubber (NR/SBR respectively) relative composition of devulcanisates indicated uneven devulcanisation when using DD, whereas MBTS did not show any form of preference. DD showed preference for NR devulcanisation over SBR. Further analysis of the sol and gel fractions were performed using; Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy, Gel Permeation Chromatography and Gas Chromatography coupled with Mass Spectroscopy. Application of the optimised conditions to devulcanise ground tyre rubber (GTR) resulted in relatively lower degrees of devulcanisation for both DD and MBTS; 41.22 ± 4.22 and 22.41 ± 1.97 respectively. The differences in the degree of devulcanisation of the laboratory prepared vulcanisates and the GTR was determined to be due to sample differences; i.e. sample constituents, particle dimensions and crosslink network (crosslink distribution in particular).
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  • Date Issued: 2019

Differences in the use of surface water resources by desert birds are revealed using isotopic tracers

  • Authors: Smit, Ben , Woodborne, Stephan , Wolf, Blair O , McKechnie, Andrew E
  • Date: 2019
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/440532 , vital:73790 , https://doi.org/10.1093/auk/uky005
  • Description: The scarcity of free-standing water sources is a key determinant of animal and plant community structure in arid environments, and an understanding of the extent to which particular species use surface water is vital for modeling the effects of climate change on desert avifauna. We investigated interspecific variation in the use of artificial water sources among birds in the Kalahari Desert, South Africa, by (i) observations at waterholes and (ii) tracing spatial water-use patterns during summer by isotopically labeled water sources and blood sampling. More than 50% of the avian community (primarily insectivores and omnivores) were not observed to drink. The majority (53%) of species drinking at waterholes were granivorous, and their use of surface water was best predicted by their relative abundance in the community. Species representing the remaining dietary guilds drank significantly more on hot days. Blood samples revealed that only 11 of 42 species (mostly granivores and a few omnivores) showed evidence of drinking at a waterhole with enriched deuterium values; on average, in the latter birds, water from the enriched waterhole accounted for ~38% of their body water pool. These findings illustrate that 2 methods employed in this study provide different, but complementary data on the relative importance of a water source for an avian community. Although our results suggest that most avian species are independent of surface water, drinking patterns on the hottest days during our study period suggest that free-standing water might become more important for some of the non-drinking species under hotter climatic conditions.
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  • Date Issued: 2019

Differentiated Instruction: A Study of English Second Language Teachers’ Awareness and Implementation in Selected High Schools in the Eastern Cape Province

  • Authors: Ndu, Onyinyechi Glory
  • Date: 2019
  • Subjects: English language -- Study and teaching Language and languages -- Study and teaching
  • Language: English
  • Type: Thesis , Doctoral , D Lit. (English)
  • Identifier: http://hdl.handle.net/10353/11440 , vital:39072
  • Description: The lack of visible academic excellence in South Africa has necessitated the search for a more in-depth approach in teaching and learning. The Department of Basic Education, school administrators and School Governing Bodies are not left out in the search for a distinct approach that would be able to assist teachers and also accommodate diverse learning abilities found in the classroom. The purpose of this study is to investigate English Second Language teachers’ awareness and implementation of differentiated instruction in selected high schools in the Eastern Cape Province, South Africa. The objectives were to find out the extent to which teachers adopt differentiated instructions in their classes: to examine teachers’ narratives about differentiated instruction and the alternative instruction teachers’ use in their classrooms. The study was anchored on the socio-cultural theory, multiple intelligence theory and learning style theory. It employed a mixed method research and triangulation, which was very beneficial for the validation of the research findings. It followed a case study exploratory design and descriptive survey design. A purposive sample of hundred and six (106) participants were used in the study. The quantitative data were analysed using tables, frequencies and percentages while the qualitative data were analysed thematically. The findings of the study revealed that ESL Grade 10 high school teachers were not aware of the term “Differentiated Instruction” even though to some extent they adopted DI approach. Teachers had mixed narratives about DI implementation and they used different alternative instructions during their lessons. The researcher recommended that teachers should be introduced to DI approach and be given more assistance, motivation, exposure and trainings in the form of conferences and seminars on proper DI implementation. Also teachers should be encouraged to continuously develop themselves academically in order to adjust to the new trend of managing the diverse learners that exist in their classes and in differentiating instruction with technology.
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  • Date Issued: 2019

Digital colonialism: South Africa’s education transformation in the shadow of Silicon Valley

  • Authors: Kwet, Michael
  • Date: 2019
  • Subjects: Operation Phakisa Education (South Africa) , Educational technology -- South Africa , Internet in education -- South Africa , Educational sociology -- South Africa , Technological innovations -- South Africa , Technological literacy -- South Africa , Education and state -- South Africa , Open source software -- South Africa , Electronic surveillance -- Social aspects -- South Africa , Privacy, Right of -- South Africa , Business and education -- South Africa
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/93767 , vital:30936
  • Description: This dissertation investigates the social implications of technology choices for the emerging education transformation of the South African basic education sector. In October 2015, then President Jacob Zuma launched Operation Phakisa Education (OPE), an initiative designed behind closed doors to fast-track digital education into all South African public schools. This study identifies and analyses policy choices and perspectives regarding the technology considered and deployed for the national education rollout. It documents the OPE proposal, and examines how e-education policy choices relate to humanitarian objectives. Theoretically, this study draws upon libertarian socialist theory (anarchism) to examine the sociology of education technology policy. Using anarchist theory, it assesses the perspective, aims, and choices of e-education policy at the national level. It also draws on the Free Software philosophy for society as articulated by Richard Stallman and Eben Moglen. Finally, it compares classic colonialism with global power in the digital era, and posits a theory of digital colonialism. Synthesizing anarchism and the Free Software philosophy into a single theoretical framework – placed into the context of colonial relations – it is the first work to apply anarchist sociological theory to education technology policy, and the first doctoral study on digital colonialism. For its methodology, this dissertation utilizes two qualitative methods: document analysis and semi-structured interviews. Interview subjects include high-level e-education policymakers and administrators in government, key stakeholders, and experts at the intersection of technology innovation and human rights. These methods were used to both identify and interrogate e-education policy as it relates to the humanitarian objectives of education policy at the national level. The findings demonstrate that South African education policy is beholden to largely United States-based corporations and models for e-education. The study found that the types of technologies for consideration in education are rooted in surveillance capitalism, which is spreading across the world. It contends that current e-education policy choices will entrench the power and exploitation of US state-corporate power in South African education, economy, and society. It argues that an alternative set of choices, People’s Technology for People’s Power, is consistent with the spirit of South African technology policy, and should be chosen for South African schools in order to counter the power of foreign power and resist surveillance capitalism. This dissertation is the first publication to document and analyze what the new government education policy is about and how it relates to equality and human rights. It argues that present South African e-education policy constitutes a new form of digitally-driven technocratic neoliberalism which ultimately favors ruling class interests in the United States and South Africa. It also argues that OPE violates South Africa’s Free and Open Source policy and the spirit of democracy outlined in the Phakisa methodology and the Batho Pele principles. This study found that OPE replicates the latest trends in e-education implementation popular in Silicon Valley. Tech multinationals are providing both the products and models for use in South Africa. The dissertation concludes that US technological and conceptual dominance in South African education constitutes digital colonialism. It emphasizes the need for public inclusion in the policy process, and proposes alternative policies and technologies for e-education based on the idea of People’s Technology for People’s Power. It also argues that current scholarship on education technology neglects the political and sociological importance of People’s Technology to education, economy, and society, as well as the global significance of Big Tech dominance vis-a-vis digital colonialism, and that subsequent literature would be enriched by addressing these issues.
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  • Date Issued: 2019

Discorhabdin N, a South African Natural Compound, for Hsp72 and Hsc70 Allosteric Modulation: combined study of molecular modeling and dynamic residue network analysis

  • Authors: Amusengeri, Arnold , Tastan Bishop, Özlem
  • Date: 2019
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/162949 , vital:40999 , https://doi.org/10.3390/molecules24010188
  • Description: The human heat shock proteins (Hsps), predominantly Hsp72 and Hsp90, have been strongly implicated in various critical stages of oncogenesis and progression of human cancers. While drug development has extensively focused on Hsp90 as a potential anticancer target, much less effort has been put against Hsp72. This work investigated the therapeutic potential of Hsp72 and its constitutive isoform, Hsc70, via in silico-based screening against the South African Natural Compounds Database (SANCDB). A comparative modeling approach was used to obtain nearly full-length 3D structures of the closed conformation of Hsp72 and Hsc70 proteins. Molecular docking of SANCDB compounds identified one potential allosteric modulator, Discorhabdin N, binding to the allosteric β substrate binding domain (SBDβ) back pocket, with good binding affinities in both cases.
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  • Date Issued: 2019

Discursive psychological analysis on the construction and performance of identity through rights talk on social media related to #FeesMustFall

Dismissal for ill health or injury and reasonable accommodation for disabled employees

  • Authors: Mabenge, Mfundiso Samson
  • Date: 2019
  • Subjects: Employees -- Dismissal of -- Law and legislation -- South Africa , Labor laws and legislation -- South Africa Discrimination in employment -- South Africa
  • Language: English
  • Type: Thesis , Masters , LLM
  • Identifier: http://hdl.handle.net/10948/34755 , vital:33437
  • Description: This treatise examines the challenges faced by people with disabilities, in particular, dismissal and discrimination at the workplace. The study employed a qualitative approach to explore and address the research questions. It highlights that the Constitution provides protection against discrimination on the ground of disability. This right not to be discriminated against or unfairly dismissed is further given effect by the Codes of Good Practice in both the EEA and the LRA. Dismissal on a prohibited ground of discrimination, such as disability, is not merely unfair, but automatically unfair. Despite the above legislative protection, the findings in this study indicate that South Africa still faces huge challenges of disability discrimination and dismissal. Notwithstanding the increased sensitivity of this subject across the country, applicants for work and employees generally find themselves to be the victims of employment discrimination as well as dismissal due to their disability. Those who are in the working sector are not reasonably accommodated. The study submits that people with disabilities should be reasonably accommodated and be retained in the working sector as they have a positive role to play in the economy. In terms of legislation, the study found that although well written in theory, they are practically ineffective given that they are fragmented. This study observes that single legislation dealing comprehensively with disability management, like in other jurisdictions does not exist in South Africa. The lack of such single legislation is a significant weakness in the South African disability management framework. Therefore, this has resulted in a fragmented approach to implementation. The study suggests that trade union representatives and employers should be well trained, particularly on issues relating to dismissal for incapacity in general. From a global perspective, international organisations through ratifying Conventions have also heeded to the plight of disabled persons. This is proof that disability can no longer be confined to the borders of one nation. Many disability organisations have emerged over the years and are representing the interests of the disabled. The findings of this study may help companies, organisations and institutions improve their policy practices regarding the dismissal of employees associated with ill health or injury.
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  • Date Issued: 2019

Disrupting the familiar family in postcolonial literature

  • Authors: Laubscher, Emma Kate
  • Date: 2019
  • Subjects: Postcolonialism in literature , Families -- Fiction , Interpersonal relations in literature , Families in literature , Gender identity in literature , Gappah, Petina, 1971- -- Criticism and interpretation , Enright, Anne, 1962- -- Criticism and interpretation , Owuor, Yvonne Adhiambo
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10962/153757 , vital:39516
  • Description: Anne Enright’s The Green Road, Petina Gappah’s The Book of Memory and Yvonne Adhiambo Owuor’s Dust offer various disruptive representations that challenge the normative family, and allow for an excavation of the potency and pervasiveness of the notion of family as an organising social principle, in a postcolonial context. Through these novels’ depictions of unorthodox families, it becomes possible to unpack the metaphorical architecture that underpins the normative family – by which I mean that social formation which enables and relies upon gender binaries, heteronormative constructions of sexuality and exclusionary racial structures. Additionally, I will attempt to examine the role that the normative family plays in shaping the subject, and determining its avenues of association, through encountering the disruptive possibilities portrayed in Gappah, Owuor and Enright’s works. My analysis is concerned with how the family orientates the subject in particular ways that regulate and delimit the subject’s means of relating to herself, those who surround her and the historic and mnemonic pasts in which she is embedded. In representing alternate kinship structures, these novels expand the aesthetic and imaginative landscape of the family and allow for new forms of relation to emerge. These transgressive and radical ways of being, knowing and loving have disruptive consequences for those social formations which are structured by, and draw on, the family – in particular the nation state. This reworking of the nation state, as well as the destabilisation of the relations between nations states, provides new avenues for inhabiting the postcolonial world. In particular, my reading argues that representations of the unfamiliar family offer different ways of receiving and relating to the self, others, and the past within a social order ruptured by the violent legacies of colonisation.
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  • Date Issued: 2019

Distribution of virulence determinants in some members of the ESKAPE pathogens isolated from selected hospital wastewater effluents in the Eastern Cape, South Africa

  • Authors: Mapipa, Qaqamba
  • Date: 2019
  • Subjects: Effluent quality Water -- Purification
  • Language: English
  • Type: Thesis , Masters , MSc (Microbiology)
  • Identifier: http://hdl.handle.net/10353/14704 , vital:40061
  • Description: Members of ESKAPE pathogens are grouped under the acronymn made up of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species. ESKAPE pathogens, isolated from hospitals and communities, have just been characterized for new pathogenesis and transmission patterns and overcoming the usefulness of available drugs, this leads to infections that tend to increase the rate of disease in a population and death rate and cost our society massively. The distribution of virulence determinants and the antibiotic susceptibility patterns in some members of the ESKAPE pathogens isolated from hospital wastewater facilities that were selected within the Eastern Cape Province, South Africa was evaluated. Water samples from the hospital wastewater facilities were collected fortnightly over a period of three (3) months (February to April). Spread plate technique was employed for the enumeration and isolation of the members of ESKAPE pathogens. A total of 725 presumptive ESKAPE isolates were collected, screened and Polymerase Chain Reaction (PCR) amplification of target determinants was performed. Results showed that Klebsiella pneumoniae tested positive for ninety two (92=35.9%) samples, Enterobacter cloacae fifty seven (57=22.2%) samples tested positive, Pseudomonas aeruginosa fifty four (54=21.09%) isolates tested positive and fifty three (53=20.7%) isolates tested positive for Acinetobacter baumannii making a total of 256 isolates which tested positive for some members of ESKAPE pathogens. The detection of some members of the ESKAPE pathogens in these Hospitals is a cause of concern to public health. A total of 256 ESKAPE isolates that were obtained from the hospital wastewater facilities; were subjected to antibiotic susceptibility test in order to determine their antibiotic-resistant profiles. ESKAPE isolates recovered from the three hospital effluents showing resistance to antimicrobial agents in this study were further evaluated for resistance determinants namely, sulfonamides resistance determinants (sulI and sulII), β-lactams (ampC, blaTEM and blaZ), tetracyclines (tetA, tetB, tetC and tetM), 10 chloramphenicol’s (catI and catII) and aminoglycoside resistance determinants (aacC2, apHAI and apHAII). The resistant determinants targeted have been evaluated through their prevalence and the following distributions were obtained: [β-Lactams; ampC (80%), blaTEM (77%)]; [Tetracyclines; tetA (87%)]; [Sulfonamides; sulI (79%)]; [Aminoglycosides; aacC2 (12%), aphA2 (52%) and aadA (18%)]. With the worldwide increase in these resistant occurrences, the execution of strict infection control policies and treatment with different antimicrobials needs hasty detection. Comprehensive data are therefore needed so that the history of infection, identification of genes present in organisms and monitoring of changes in infection patterns can be traced correctly.
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  • Date Issued: 2019

Diversity, host plant range and ecology of Lepidoptera stem borers in South Africa

  • Authors: Stemele, Mxolisi Arnold
  • Date: 2019
  • Subjects: Lepidoptera Host plants Stem borers
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10353/15409 , vital:40405
  • Description: The biology and ecology of Lepidopteran pests stem borers has been extensively studied because of the economic importance of pest species such as Busseola fusca (Fuller) (Noctuidae), Sesamia calamistis (Hampson) (Noctuidae), Chilo partellus (Swinhoe) (Crambidae), and Eldana saccharina (Walker) (Pyralidae). Knowledge relating to diversity, infestation dynamics, and host plant range is readily available. In natural vegetation, the variety of stem borers is higher than that found in agroecosystems. However, there is a paucity of South African studies that explain the observed differences in diversity between the two systems. Stem borers are also known to exhibit species-specific ecological requirements, which influence their distribution between African countries. South African biomes are classified based on vegetation structure and climate, which happens to be the most critical factors that affect the distribution of phytophagous insects. This makes biomes an excellent model to investigate diversity and distribution of stem borer species. In this study, we investigated diversity, distribution and species composition in four biomes. The results showed that diversity and distribution of the stem borers in natural vegetation was determined by host plant distribution. Stem borer diversity correlated with high diversity of host plants. Thirty-two stem borer species were collected from 27 host plants and another three from light traps. Widely distributed host plants supported a higher diversity of stem borers, which is consistent with the resource availability hypotheses. Non-metric dimensional scale unfolding revealed disparity in host plant preference and plant species composition between the various stem borer families (Kruskal’s Stress = 0.16). Tortricidae species and Sesamia typhae (Le rü) (Noctuidae) feed exclusively on hydrophytic Cyperaceae species. The majority of Noctuidae, Crambidae and Phycitidae species collected were oligophagous on terrestrial Poaceae, with a few polyphagous exceptions feeding on hydrophytic Cyperaceae and Typhaceae. Additionally, species composition of Poaceae host plants differed between 8 Crambidae and the Phycitidae species. Stem borer species composition between biomes revealed the presence of distinct host plants (2D stress = 0.09) and stem borer (2D stress = 0.13) communities. The stem borer abundance and diversity were strongly correlated (R2 = 0.64), but species diversity (R2 = - 0.95) and host plant diversity (R2 = - 0.85) were inversely correlated to altitude. Based on these results it was concluded that stem borer diversity and distribution in natural vegetation was influenced by host plant diversity and distribution as well as climate associated with altitudinal gradients. In the last two decades, four stem borer species previously known on wild host plants; Busseola segeta (Bowden), Busseola phaia (Bowden), Pirateolea piscator (Fletcher) and Conicofrontia sesamoides (Hampson) have invaded cultivated crops. These invasions remained undetected because of a shortage of surveys, habitat transformation and misidentifications. Misidentifications are common among stem borers due to the considerable resemblance between morphospecies. In this study, we assessed the capacity of the mitochondrial gene Cytochrome c oxidase (COI) to delineate closely related species to develop monitoring and early detection of invasive species and to assess migration patterns and gene flow between the populations. The results demonstrated that COI is an effective DNA marker for species delineation and assessment of intra- and interspecific genetic relationship. The K2P distances and phylogenetic tree defined boundaries between Noctuidae species with high resolution. No divergence distance was detected between intraspecific species, but for the congener species, divergence distance was 0.044%-0.111% with an average of 0.076%. The average interspecies K2P distance (0.57%) was 5-15 times higher than the congener species distances. Phylogenetic analysis revealed the presence of two clades. Busseola and Sesamia species were connected in a monophyletic clade with a strong (93%) bootstrap. The second monophyletic clade comprised of a cluster of Pirateolea, Acrapex and Conicofrontia species, and this was also supported with 9 a strong bootstrap (100%). The gene flow study revealed low levels of genetic differentiation between the populations of B. fusca collected from different maize producing areas in South Africa. This low genetic differentiation was consistent with high gene flow. The number of effective migrants between the populations was between 8 and 99 individuals per generation. These results indicate high connectivity between the populations.
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  • Date Issued: 2019

Do FDI and public investment crowd in/out domestic private investment in the SADC region?

  • Authors: Ngeendepi, Eslon J
  • Date: 2019
  • Subjects: Investments, Foreign -- Africa
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: http://hdl.handle.net/10948/49997 , vital:41968
  • Description: This paper attempts to contribute to empirical literature on investment theory by examining whether FDI inflows and government capital expenditure crowd-in/out domestic private investment in 15 SADC member states for the period 1991-2017. In order to realise the study objective, the panel Pool Mean Group (PMG)/ARDL technique was employed in estimating the shot-run and long-run relationship between FDI, government capital expenditure, domestic private investment and a further three more variables (interest rate, GDP growth rate and trade openness.) added to the model to form multivariate framework. Findings from the study show that FDI inflow crowd-in domestic private investment in both the short and long run, while government capital expenditure is found to crowd-out domestic private investment in the long-run and crowd-in domestic private investment in the short-run. The study concludes by providing policy recommendations and suggesting areas for further research.
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  • Date Issued: 2019

Dual phototransformation of the pollutants methyl orange and Cr (VI) using phthalocyanine-cobalt ferrite based magnetic nanocomposites

  • Authors: Mapukata, Sivuyisiwe , Osifeko, Olawale L , Nyokong, Tebello
  • Date: 2019
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/187059 , vital:44561 , xlink:href="https://doi.org/10.1016/j.heliyon.2019.e01509"
  • Description: Bifunctional nanocomposites based on zinc phthalocyanines and glutathione capped CoFe2O4 magnetic nanoparticles (GSH-CoFe2O4 MNPs) are applied in a binary system wherein simultaneous photooxidation of methyl orange (MO) and photoreduction of Cr (VI) are conducted. The photoactivity of two zinc Pcs with different functional moieties are compared based on their interactions with GSH-CoFe2O4 MNPs. Conjugation of the Pcs to the GSH-CoFe2O4 MNPs not only enhanced their singlet oxygen production but also their photocatalytic activity in both photooxidation and photoreduction experiments. Using electron paramagnetic resonance (EPR) spectroscopy, the Pc-MNP conjugates reported herein were found to exhibit superparamagnetic behaviour, giving the advantage of easy separation using an external magnetic field post application, an attractive attribute for heterogeneous catalysis. The catalysts reported herein are therefore good candidates as catalysts for real life water purification analyses as they facilitate the treatment of both organic and inorganic water pollutants.
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  • Date Issued: 2019

E-books preference compared to print books based on student perceptions: a case of University of Fort Hare students

  • Authors: Makwanya, Comfort
  • Date: 2019
  • Subjects: Electronic books College students
  • Language: English
  • Type: Thesis , Masters , MCom (Business Management)
  • Identifier: http://hdl.handle.net/10353/13653 , vital:39688
  • Description: Technology has been shifting students’ perceptions and preferences on how they learn. The way in which students perceive print books and e-books greatly affects which format they prefer to use for academic purposes. In recent years, e-book accessibility on a variety of mobile gadgets has become a substitute to print based resources which are costly in terms of production, sharing and heavy in terms of their physical nature. Institutions of higher learning have decided that e-books and related resources are the most preferred options among students. This, however, is in contrary to the research findings which propound that students do not actually favour e-books. The intention of this study was to determine students’ perceptions with regards to using e-books and print books in meeting information needs. In addition, the study aimed to determine students’ awareness, usage, preference and students’ plan to adopt e-books as their only source of information in the future. Contrasting views exist on which format (print or e-book) students prefer for academic purposes to enhance their learning experience with most studies being done in developed countries. Hence, the investigation that uncovers students’ perceptions and preferences towards the two formats in South Africa can provide a better comprehension and conclusion on an African student. This will consequently lead to improved student engagement and improved learning outcomes. A cross-sectional research design was used and a questionnaire administered to a sample of 307 students at the University of Fort Hare’s East London Campus through convenience sampling. Findings from this study showed that students at the University of Fort Hare’s Faculty of Management and Commerce preferred using both (e-books and print books) for their information needs. They also perceived e-books as good as print books, easier and friendly to use and capable of providing adequate information to meet study needs. The findings will assist practitioners to understand readers’ needs, improve awareness, and develop e-book collections and designs that improve the learning process.
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  • Date Issued: 2019

Early Jurassic dolerites of the Karoo Large Igneous Province ( KLIP): an analysis of their age and emplacement history from sea level to the Drakensberg Mountains in the Eastern Cape , South Africa Submitted

  • Authors: Muedi, Thomas Tshifhiwa
  • Date: 2019
  • Subjects: Geological time , Geochemistry Geology -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/41908 , vital:36608
  • Description: South Africa hosts one of the largest Large Igneous Provinces (LIPs that is likely linked to the early separation of East and West Gondwana. However, despite many studies, the relationship between dolerites and volcanic basalts of this LIP (also known as the Karoo Large Igneous Province or KLIP) remains unsolved, because of poorly linked age dates (timing), geochemistry and emplacement mechanisms. This problem is in part because different unreliable dating techniques with large margin of errors have been applied This study aims to address these issues by performing new geo chemical and high resolution geochronological analyses on a number of dolerites (sills and dykes), volcanic s also referred to in the literature as the Drakensberg flood basalts) and samples from drill cores and field outcrops. This project is focused on dolerites in the Eastern Cape Province and provides results from field mapping of dolerites (sills and dykes) from the sea level to an elevation of circa 1350 metres above sea level (MASL) and their link to the volcanic in the Eastern Cape Province. The dolerite dykes observed trends from metres to hundreds of kilometres and cut across volcanic, which have similar geochemistry. The intrusive dolerites collected from the field and from d rill core samples were likely emplaced by magma infiltration through pre-existing sub vertical brittle fractures and fissures and then emplaced horizontally as sills circa 183 Ma Detailed fracture mapping across host rock to the dolerite was carried out to test if they acted as possible pathways for magmatic emplacements. The dolerite dykes and fractures mapped in the host sedimentary rocks have a dominant NW direction, especially towards volcanic basalts. The project provides tests based on the geochemical relationships of the dolerites and basalts from sixty-six (66) cores and field outcrop samples. The results confirm that the chemical analyses from the volcanic basalts an d dolerites are closely related and reveal that most samples are Ocean Island Basalt OIB), but some also reveal subduction related processes. This is consistent with models that suggest subduction along south west Gondwana may have influenced plumemagmatism derived from the lower mantle that initiated break up of this supercontinent e.g de Wit and Stern 1981 Storey et al , 1992 ; Torsvik et al., 2006 and Burke et al., 2008)
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  • Date Issued: 2019

Ecological assessment and biogeography of coastal vegetation and flora in southern Mozambique

  • Authors: Massingue, Alice Obed
  • Date: 2019
  • Subjects: Coastal plants -- Mozambique , Coastal plants Marine biodiversity -- Mozambique Coastal biodiversity -- Mozambique
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10948/40988 , vital:36280
  • Description: This study considered aspects of the vegetation of the coastal zone of southern Mozambique, an area with a rich biodiversity. The vegetation and flora were assessed in their current state including the associated anthropogenic pressures. The environmental conditions that determined the distribution of the vegetation were evaluated. A hierarchical classification, description and ecological interpretation of the vegetation and flora of the coastal zone in southern Mozambique are presented. Analysis was based on 242 sample quadrats that were distributed in a stratified manner throughout the study area. The vegetation could be grouped into six distinct types of vegetation: Dune Forest, Coastal Forest, Coastal Grassland, Coastal Miombo, Coastal Savanna and Coastal Woodland. Species diversity was high for the all the vegetation types, particularly in the woody elements. A total of 673 species in 410 genera was recorded. They represented 104 families with Fabaceae and Rubiaceae being the most common. Of these, 6.6% were endemic or near-endemic to the coastal zone of southern Mozambique with Coastal Forest being the habitat with the greatest endemism. All soils from different vegetation types had poor agricultural potential. Soil properties were the strongest defining environmental feature separating the vegetation types: e.g. pH was high in Dune Forest compared to the others. Results from Maxent modelling suggest that the distribution of endemic species is influenced by a combination of climatic and non-climatic variables. Soil type, temperature annual range and precipitation of the driest month were the most important predictor variables. Overlaying the potential distributions of the seven selected species indicated two areas of abundance of endemic species – these should be given attention for conservation. Endemic species are not well protected in southern Mozambique – their sampled and potential habitats are largely outside protected areas. Hence, additional reserves should be created to improve their protection. Most endemic and near-endemics species were found in the south, from Ponta de Ouro (Matutuine, south of Maputo Province) to Manhica district (north of the Maputo Province) forming part of the Maputaland Centre of Endemism. A second concentration of endemism was found in the Inhambane Province, specifically the Inhassoro and Vilanculos districts. This is proposed to be an Important Plants Area (IPA). Because most endemics and near-endemics are found in the Coastal Forest, their main threat is harvesting for charcoal production, although none of the endemic species are specifically targeted for charcoal production. In Inhambane they are also threatened by the tourism industry, agriculture and settlements. The impact of the habitat destruction on endemic species is expected to cause severe declines in the near future. The tourism industry and harvesting of trees for charcoal production and over-frequent fires are the main drivers of vegetation loss in this region. Shifting agriculture, harvesting for firewood and construction materials, cattle grazing (at a minor scale) are also impacts, but these were only observed in a small area of Maputo Province. Although the study was done in coastal zone of southern Mozambique, effective management of whole coastal zone of the country will be required to maintain a functioning and diverse ecosystem. Priorities for management are to ensure that forests are protected, in particular, Dune Forest. Actions are required to minimise degradation of coastal vegetation. Further research on Coastal Forest restoration should be planned, as field observations in this study confirm that forest in the coastal zone of southern Mozambique has resilience.
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  • Date Issued: 2019

Ecological connectivity between the areas beyond national jurisdiction and coastal waters: Safeguarding interests of coastal communities in developing countries

  • Authors: Popova, Ekaterina , Vousden, David , Sauer, Warwick H H , Mohammed, Essam Y , Allain, Valerie , Downey-Breedt, Nicola , Fletcher, Ruth , Gjerde, Kristina M , Halpin, Patrick , Kelly, Stephen , Obura, David , Pecl, Gretta T , Roberts, Michael J , Raitsos, Dionysios E , Rogers, Alex , Samoilys, Melita , Sumaila , Ussif Rashid , Tracey, Sean , Yool, Andrew
  • Date: 2019
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/124331 , vital:35594 , https://doi.10.1016/j.marpol.2019.02.050
  • Description: The UN General Assembly has made a unanimous decision to start negotiations to establish an international, legally-binding instrument for the conservation and sustainable use of marine biological diversity within Areas Beyond National Jurisdiction (ABNJ). However, there has of yet been little discussion on the importance of this move to the ecosystem services provided by coastal zones in their downstream zone of influence. Here, we identify the ecological connectivity between ABNJ and coastal zones as critically important in the negotiation process and apply several approaches to identify some priority areas for protection from the perspective of coastal populations of Least Developed Countries (LDCs). Initially, we review the scientific evidence that demonstrates ecological connectivity between ABNJ and the coastal zones with a focus on the LDCs. We then use ocean modelling to develop a number of metrics and spatial maps that serve to quantify the connectivity of the ABNJ to the coastal zone. We find that the level of exposure to the ABNJ influences varies strongly between countries. Similarly, not all areas of the ABNJ are equal in their impacts on the coastline. Using this method, we identify the areas of the ABNJ that are in the most urgent need of protection on the grounds of the strength of their potential downstream impacts on the coastal populations of LDCs. We argue that indirect negative impacts of the ABNJ fishing, industrialisation and pollution, communicated via oceanographic, cultural and ecological connectivity to the coastal waters of the developing countries should be of concern.
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  • Date Issued: 2019

Econo-Language Planning and Transformation in South Africa: From Localisation to Globalisation

  • Authors: Kaschula, Russell H
  • Date: 2019
  • Language: English
  • Type: text , book
  • Identifier: http://hdl.handle.net/10962/174657 , vital:42498 , ISBN 9781108425346
  • Description: This chapter seeks to create an understanding of the historical, sociopolitical and economic context within which language planning has taken place in South Africa (Alexander 1992). Furthermore, the extent to which government agencies and other stakeholder bodies have taken language planning into account when developing economic and development policies within the contemporary global reality will be assessed (Edozie 2004). Policies (if one can call them policies) such as the New Partnership for Africa’s Development (NEPAD), as well as the National Development Plan (NDP) in South Africa are analysed against the backdrop of language policy planning and implementation, to see if there are linkages between opportunity language planning on the ground (Antia 2017) and economic development. In other words does language planning create work opportunities through policy creation and implementation where our languages are seen as resources to be used appropriately in the market place?.
  • Full Text:
  • Date Issued: 2019

Ectomycorrhizal fungal assessment of South African Pinus patula seedlings and their biological control potential to enhance seedling growth

  • Authors: FitzGerald, Véronique Chartier
  • Date: 2019
  • Subjects: Ectomycorrhizal fungi , Pinus patula Diseases and pests Biological control South Africa , Fusarium , Forest nurseries , Seedlings Growth , Seedlings Diseases and pests
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10962/67902 , vital:29167
  • Description: The South Africa forestry industry, covering 1.3 million hectares, is dependent on exotic pine and eucalyptus species. Nursery seedlings are not inoculated with ectomycorrhizal (ECM) fungi or other beneficial microbes. Fusarium circinatum is an economically important pathogen affecting seedling survival. The purpose of this investigation was to assess levels of naturally occurring ECM colonisation in South African nurseries and to determine the effects of seedling inoculation with selected ECM and bacterial isolates on plant growth and resistance to the fungal pathogen F. circiantum. Pinus patula seedlings from 10 different South African nurseries were assessed for ECM colonisation using a grid line intersect method and molecularly identified using morphological and next-generation Illumina sequencing. Explants from ECM basidiocarps, collected from Pinus stands, were plated onto MMN medium to obtain isolates which were verified using molecular techniques. Mycorrhizal helper bacteria (MHB) were also isolated from these basiocarps, tested for MHB properties, siderophore production, phospahte solubilising and IAA production. ECM and associated bacterial isolates were used to inoculate seedlings and growth was assessed over a 5 month period. Colonisation of seedlings in production nurseries was low (2-21%). Morphologically the ECM fungi T. terrestris, Suillus sibiricus, and the genera Russula, Pseudotomentella were identified. Molecularly the ECM fungi T. terrestris, Inocybe jacobi and the genera Sphaerosporella and several other ECM containing families were identified along with many saprotrophic/endophytic fungi belonging to genera such as, Penicillium, Ramasonia and Talaromyces. Inoculated seedlings showed a significant increase in growth in comparison to the un-inoculated control seedlings. ECM fungal colonisation levels of these seedlings were significantly increased and colonisation was promoted by the Suillus isolate, Salmon Suillus. Seedling growth in the presence of the pathogen F. circinatum was significantly increased and promoted by the Lactarius isolate Lactarius quieticolor. Inoculation of seedlings in the nursery would ensure the production of stronger healthy plants which may be more tolerant to fusarial infection increasing survival in the plantation. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2019
  • Full Text:
  • Date Issued: 2019
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